Look for a pattern and find the next two numbers in the sequence and then write a general version of the nth term.
1 2 3 4 5 6 7 8 n
18 30 42 54 66 78
I can recognize the pattern as being + 12 so under 7 my answer would be 90 and under 8 my answer would be 102, but how do I figure out what the nth term would be?